Diammonium hydrogen phosphate → 5-Bromo-3-cyanoindole

HRID 2355948Notes

Reaction equation

HRID 2355948 reaction equation
[Br:1][C:2]1[CH:3]=[C:4]2[C:8](=[CH:9][CH:10]=1)[NH:7][CH:6]=[C:5]2[CH:11]=O.P([O-])([O-])(O)=O.[NH4+:18].[NH4+]>[N+](CCC)([O-])=O.C(O)(=O)C>[Br:1][C:2]1[CH:3]=[C:4]2[C:8](=[CH:9][CH:10]=1)[NH:7][CH:6]=[C:5]2[C:11]#[N:18]

Participants

5

Reactant 2

HCID 24540Diammonium hydrogen phosphateHCID 701375-Bromoindole-3-carbaldehyde

Product 1

HCID 36233545-Bromo-3-cyanoindoleYield 87.2%

Reagents, catalysts & solvents 2

HCID 176Acetic AcidSolventHCID 79031-NitropropaneSolvent

Procedure

A mixture of 5-bromo-indole-3-carboxaldehyde (5 g, 22.3 mmol), diammonium hydrogen phosphate (15.6 g, 31.8 mmol) in 1-nitropropane (66 mL) and acetic acid (22 mL) were heated at reflux for 16 h. After cooling to room temperature, the solvents were removed under reduced pressure and water added to the dark residue. After a short while, 5-bromo-1H-indole-3-carbonitrile precipitated rapidly. The solid was filtered, washed severally with water and dried for several hours to afford 4.3 g (86%) of the desired product. 1H-NMR (CD3OD) δ 7.40 (m, 2H), 7.77 (s, 1H), 7.97 (s, 1H). Mass spec.: 222.95 (MH)+.

Workup

  1. temperaturewere heated
  2. temperatureat reflux for 16 h
  3. customthe solvents were removed under reduced pressure and water
  4. additionadded to the dark residue
  5. customAfter a short while, 5-bromo-1H-indole-3-carbonitrile precipitated rapidly
  6. filtrationThe solid was filtered
  7. washwashed severally with water
  8. customdried for several hours

Sources & evidence

ORD record
ord-00710ccce35f48f8bdc5408f9f530430
Source dataset
uspto-grants-2010_07
Patent number
US07754732B2

Reaction notes

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